1. Field of the Invention
This invention relates to an apparatus and method for lifting pipes and related objects. More particularly, the invention relates to a magnetically activated toggle device which can be mounted on a prime mover, can raise and lower heavy objects, and can rotate or hold the objects in a fixed position.
2. Technical Background
Heavy, large pipes are used to transport fluids such as, for example, water, sewage, and gasoline. These pipes are usually lifted from trucks and lowered into ditches and removed in a similar fashion. Often these pipes are precast in concrete sections and have a hole in the side of the pipe at the lengthwise center of the section. A common method for lifting and lowering these pipes is to use a cable with a loop and a pin inserted through the loop. The cable is attached at one end to a crane and the loop is at the opposite end of the cable. The loop is passed through the hole in the pipe and advanced into the interior of the pipe. A person outside the pipe is required to pass the loop through the hole into the pipe and another person is required inside the pipe to insert a pin (such as a crowbar) through the loop, forming a toggle. The cable is then lifted until the pin engages the inside surface of the pipe. The pipe can then be lifted. This procedure is relatively dangerous to the person inside the pipe. The person inside the pipe usually has to hold the pin until the slack in the cable is taken up and to orient the pin along the longitudinal axis of the pipe. Accordingly, injuries to fingers and hands have been common using this method.
In order to overcome the problems associated with a person having to enter the interior of these pipes and manually place a pin, several toggle devices have been created. The toggle is attached pivotally to the end of a vertical shaft. The toggle is in a vertical position as it is passed through the hole in the pipe. Once inside the pipe, the toggle is switched to the horizontal position, extending beyond the diameter of the hole, so the pipe can be lifted. In most cases the toggle is weighted on one end so that it is maintained in a vertical position by gravity. Most of these toggles have a shaft, chain, or cable to pull them to a horizontal position. Others are pushed or pulled to a vertical position, being constructed to assume a horizontal position by the action of gravity. Yet others are constructed without shafts, chains, or cables and need to be rotated, swung, or shaken inside the pipe to get the toggle to deviate from vertical while pulling up on the cable. Further, known toggle devices rotate freely so that it is difficult to orient them properly inside the pipe and, once engaged with the pipe, the entire pipe can rotate freely. In practical use, more than on e per son is probably required to use these toggles for proper insertion and orientation. Once in place, the pipe has to be constrained, from rotation or guided for proper orientation.
What is needed, but not provided by know n toggle devices, is a toggle device that can be attached to a prime mover, that can be used by the operator of the prime mover without the need for assistance from other persons, and that can raise, lower, rotate, hold-fixed, and move the pipe forward or backward longitudinally.
The present invention is a toggle device constructed for insertion in to large pipes, tanks, reels, and the like, in order to safely lift, rotate, lower, and position these objects. The device has a shaft having a first end and an opposite end. The toggle is pivotally attached to the opposite end so as to be maintained in a vertical position by gravity. An arm is attached to the toggle so that when the arm is pulled towards the first end of the shaft, the toggle is pivoted to a horizontal position. The arm is pulled towards the first end of the shaft magnetically by activating a solenoid. The first end of the shaft is attached to a piston of a hydraulic cylinder and the piston has a pin or bolt perpendicular to the longitudinal axis of the piston. This pin fits in spiral grooves of a sleeve attached to the hydraulic cylinder. As the piston moves in and out of the hydraulic cylinder, the piston and the shaft rotate to any desire d position and can be maintained in that position by the hydraulic cylinder. In operation, the toggle in the vertical position is inserted into a pipe through a hole in the side of the pipe. An operator rotates the toggle with the hydraulic cylinder so the toggle will be parallel to the longitudinal axis of the pipe. The operator activates the solenoid to render the toggle horizontal and then lifts the toggle device with a prime mover to which the toggle device is attached. The toggle is then in contact with the inside wall of the pipe, across the hole in the pipe, and the pipe can be lifted, rotated, and lowered. Once lowered to the ground, the pipe can be moved forward or backward along its longitudinal axis by the prime mover pushing or pulling the toggle device. To remove the toggle device from the pipe, it is advanced into the pipe sufficiently for the toggle to assume a vertical position by gravity. The toggle device is then removed through the hole in the pipe.
An advantage of the present invention is a toggle device to lift heavy objects which can be operated by a single user.
Another advantage of the present invention is a toggle device that can be automatically operated by a user from a prime mover without the user contacting the toggle device.
Another advantage of the present invention is a toggle device that has a power-operated toggle.
Another advantage of the present invention is a power driven rotating mechanism that will rotate the lifted object to any fixed position and will align the object to mate with another object.
Another advantage of the present invention is that it can be attached to any suitable prime mover, such as, for example, a bucket, excavator, track-hoe, or back-hoe.